My LinuxCNC desktop locks up periodically

This may not be a problem anyone here can help me with, but I'm hoping.

I've got LinuxCNC 2.9.x running on Debian 9.12 with a KDE desktop. LinuxCNC seems to work pretty well, but every once in a blue moon, the entire desktop seems to completely freeze. I can still move the mouse pointer around, but nothing responds to clicks or keyboard. (Running Axis.)

I am, however, able to remotely log in. Moreover, LinuxCNC seems to still be running (unless some of the config ends up on the Mesa 7i76e card?), because when I e-stopped it, the fan on my spindle kept running, and then shut itself off a few minutes later, which is something I configured in LinuxCNC. (I'm not sure how LinuxCNC is compartmentalized.)

I don't really have enough expertise in Linux to even begin to diagnose this problem. I don't know if anyone else here might have any ideas? Thanks!

What PC hardware? Some Intel chips have video issues that cause
behaviour like that. There are work-arounds for most of these issues

It's a small PC I got at Fry's:

vendor_id : GenuineIntel
model name : Intel(R) Core(TM) i3-8100 CPU @ 3.60GHz

00:00.0 Host bridge: Intel Corporation 8th Gen Core 4-core Desktop Processor Host Bridge/DRAM Registers [Coffee Lake S] (rev 08)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor PCIe Controller (x16) (rev 08)
01:00.0 VGA compatible controller: NVIDIA Corporation GK208B [GeForce GT 710] (rev a1)

It has on-board graphics but I'm using the Nvidia card

Do you have cstates disabled in the BIOS/ kernel command line?

BTW if the 7I76E is still doing things, it means LinuxCNC is still running, so its likely
its a video issue.

When the screen is frozen, You might try ssh-ing into the box and getting a kernel
log (via dmesg) to try and see if there are any suspicious entries.

Assuming it is just the deskop/window environment that's crashing, and that the CNC state is stored in a different process, is there any way to restart the desktop from the command line, and re-launch Axis such that it just adopts the current state?

If not, that would be really cool.

I don't know if cstates are disabled or not. I'm assuming that yes, I DO want them disabled?

Not sure if you can restart X and the WM without losing all the launched applications.

Can you try the Intel video to see if the problem goes away?

Hyperthreading is disabled on my CPU, that I do know.

# grep -E "cpu cores|siblings|physical id" /proc/cpuinfo | xargs -n 11 echo |sort |uniq
physical id : 0 siblings : 4 cpu cores : 4

Okay, I've disabled c-states. We'll see if that changes anything.